In South Africa there is a great need to upgrade the accessibility of rural areas. With the aid of the heavy-vehicle simulator (HVS), the Gauteng Department of Transport and Public Works and the Council for Scientific and Industrial Research (CSIR) investigated the upgrading of in situ gravel roads to the paved standard through addition of a gravel bonding surface layer only. The HVS program consisted of nine tests in which loading and environmental conditions were varied. The results of this investigation indicated that loading and environmental conditions were the dominant influences on the behavior of superlight pavements. An interim transfer function for the design of superlight pavements based on the results of the investigation is provided, together with recommendations for optimization of the transfer function.